Fuel pressure control for engine fuel systems

Patent metadata

Field	Value
Publication number	US-2016298569-A1
Application number	US-201514684780-A
Country	US
Kind code	A1
Filing date	Apr 13, 2015
Priority date	Apr 13, 2015
Publication date	Oct 13, 2016
Grant date	—

Abstract

An apparatus includes an input module structured to interpret a fuel pressure command indicative of a target fuel pressure within an accumulator and a target fuel injection characteristic, a pump module structured to control a pump assembly to provide fuel to the accumulator to maintain the target fuel pressure within the accumulator, an injector module structured to control a plurality of fuel injectors to inject fuel into an engine based on the target fuel injection characteristic, a pressure module structured to interpret pressure data regarding an actual fuel pressure within the accumulator and to determine a pressure difference between the target fuel pressure and the actual fuel pressure, and a modulation module structured to determine a final fuel injection command responsive to the pressure difference exceeding a first magnitude threshold where the final fuel injection command is based on the pressure difference and the target fuel injection characteristic.

First claim

What is claimed is:

1 . An apparatus, comprising:
an input module structured to interpret a fuel pressure command indicative of a target fuel pressure within an accumulator and a target fuel injection characteristic; a pump module structured to control a pump assembly to provide fuel to the accumulator to maintain the target fuel pressure within the accumulator; an injector module structured to control a plurality of fuel injectors to inject fuel into an engine based on the target fuel injection characteristic; a pressure module structured to interpret pressure data regarding an actual fuel pressure within the accumulator and to determine a pressure difference between the target fuel pressure and the actual fuel pressure; and a modulation module structured to determine a final fuel injection command responsive to the pressure difference exceeding a first magnitude threshold, wherein the final fuel injection command is based on the pressure difference and the target fuel injection characteristic.

2 . The apparatus of claim 1 , wherein the modulation module is further structured to determine the final fuel injection command responsive to the pressure difference exceeding the first magnitude threshold for a duration of time that exceeds a time threshold.

3 . The apparatus of claim 2 , wherein the modulation module is further structured to interpret the fuel pressure command to determine a final fuel injection command limit defining a maximum threshold value for the final fuel injection command.

4 . The apparatus of claim 3 , wherein the maximum threshold value and the target fuel injection characteristic are at least one of a fuel injection duration, an amount of fuel injected, a fuel flow rate through the plurality of fuel injectors, an engine power, and an engine torque.

5 . The apparatus of claim 4 , wherein the modulation module is further structured to adjust the final fuel injection command limit, thereby limiting the final fuel injection command such that the pressure difference is reduced below a second magnitude threshold, wherein the second magnitude threshold is less than or equal to the first magnitude threshold, and wherein the final fuel injection command limit remains constant while the pressure difference is less than the second magnitude threshold until a release condition is met.

6 . The apparatus of claim 5 , wherein the final fuel injection command limit is maintained above an authority limit.

7 . The apparatus of claim 6 , wherein the modulation module is further structured to determine that the release condition is met when the final fuel injection command drops a predetermined amount below the authority limit.

8 . The apparatus of claim 3 , wherein the modulation module is further structured to redefine the final fuel injection command limit to a fraction of a previous final fuel injection command, wherein a previous pressure difference between the target fuel pressure and the actual fuel pressure within the accumulator responsive to the previous final fuel injection command is less than the first magnitude threshold.

9 . The apparatus of claim 3 , wherein the modulation module is structured to control the final fuel injection command limit responsive to the pump assembly reaching a saturation condition.

10 . The apparatus of claim 1 , wherein the input module is coupled to an input device including at least one of an accelerator pedal and a throttle, and wherein the fuel pressure command is based on a position of the input device.

11 . A method, comprising:
receiving, by an input device, a fuel pressure command indicative of a target fuel pressure within an accumulator and a target fuel injection characteristic; controlling, by a controller, a pump assembly to provide fuel to the accumulator to maintain the target fuel pressure within the accumulator; controlling, by the controller, a plurality of fuel injectors to inject fuel into an engine based on the target fuel injection characteristic; interpreting, by the controller, pressure data regarding an actual fuel pressure within the accumulator; determining, by the controller, a pressure difference between the target fuel pressure and the actual fuel pressure; and modulating, by the controller, a final fuel injection command responsive to the pressure difference exceeding a first magnitude threshold for a duration of time greater than a time threshold.

12 . The method of claim 11 , further comprising receiving, by the input device, a final fuel injection command limit defining a maximum threshold value for the final fuel injection command, where the maximum threshold value includes at least one of a fuel injection duration, an amount of fuel injected, a fuel flow rate through the plurality of fuel injectors, an engine power, and an engine torque.

13 . The method of claim 12 , further comprising redefining, by the controller, the final fuel injection command limit based on the pressure difference exceeding the first magnitude threshold for a duration of time that exceeds the time threshold.

14 . The method of claim 13 , wherein the final fuel injection command limit is redefined to a fraction of a previous final fuel injection command, wherein a previous pressure difference between the target fuel pressure and the actual fuel pressure within the accumulator responsive to the previous final fuel injection command is less than the first magnitude threshold.

15 . The method of claim 13 , wherein the controller adjusts the final fuel injection command limit, thereby limiting the final fuel injection command such that the pressure difference is reduced below a second magnitude threshold, and wherein the second magnitude threshold is less than or equal to the first magnitude threshold.

16 . The method of claim 15 , wherein the final fuel injection command limit is maintained above an authority limit defining a minimum threshold value corresponding with the maximum threshold value of the final fuel injection command limit.

17 . The method of claim 12 , further comprising modulating, by the controller, the final fuel injection command limit responsive to the pump assembly reaching a saturation condition.

18 . A system, comprising:
an engine; an accumulator structured to provide fuel to a plurality of fuel injectors, the plurality of fuel injectors structured to inject fuel into the engine; a pump assembly structured to provide the fuel to the accumulator; a pressure sensor communicably coupled to the accumulator and structured to monitor an actual fuel pressure within the accumulator; and a controller communicably coupled to the pump assembly, the pressure sensor, and the plurality of fuel injectors, the controller structured to:
interpret a fuel pressure command indicative of a target fuel pressure within the accumulator and a target fuel injection characteristic;
control the pump assembly to provide fuel to the accumulator to maintain the target fuel pressure within the accumulator;
control the plurality of fuel injectors to inject fuel into the engine based on the target fuel injection characteristic;
determine a pressure difference between the target fuel pressure and the actual fuel pressure within the accumulator; and
determine a final fuel injection command responsive to the pressure difference exceeding a first magnitude threshold for a duration of time greater than a time threshold, wherein the final fuel injection command is based on the pressure difference and the target fuel injection characteristic.

19 . The sy

Assignees

• Cummins Inc

Inventors

• Bays Mark N
• Tidwell Michael R

Classifications

• F02D41/3836 Primary

  Controlling the fuel pressure · CPC title

• F02M63/023

  Means for varying pressure in common rails (pressure control F02D41/3845) · CPC title

• F02D2200/0404

  Throttle position · CPC title

• F02D41/3845

  by controlling the flow into the common rail, e.g. the amount of fuel pumped · CPC title

• F02D41/40

  with means for controlling injection timing or duration · CPC title